Bobbin casing and carrier for rotary-hook sewing machines



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'l R. K. HOHMNN BOBBIN CASING AND CARRIER FOR ROTARY'HOK SEWING MACHINESFiled Feb. 2s. '14921 mechanism of sewing machines and con' PatentedAng., il lt nicnnnn n., nomnann, or rnnn, INDIANA. j

@Bonnin casina ann; 4cnniainnron 'ROTARY-nookisnwnve-:i/iacnrnns,

application ined. rebruary as, 1921. Asenai no. 448,577.'

stitutes an improvement on the type disclosedk in my pendingapplication, Serial Number 224,002, iiled-March *22, 1918,-and in myPatent 1,364,279, issued. January 4,

1921. lt resides principally in the structure and arrangement ofthebobbin carrier Vand its casing which make `it possible touse ay hookmember of less diameter and periph` eral speed compared to the diameterAof the carrier and its bobbin thanheretofore, or to use a largerVcarrier and bobbin without increasing the diameter or peripheral speedof the hook member. known too great peripheral speed vofthe hook Vmemberis objectionable, and forthat reason Vits diameter should be as small aspossible, but normally its diameter cannot be reduced without reducingthe size of the bobbin and that reduction would be objectionablea Theinvention also includes cooperating` means for locking the bobbincarrier and casing against rotation while guiding one branch of thethread loop around it. The novel vfeatures will be more fully understoodfrom the following description and claims taken with the drawings. Inthe drawings:

Figure 1 is a front elevation of the parts assembled including the hook,the carrier and the casing with a bobbin in place.

Figure 2 is a central vertical section taken at right angles to Figurel.

Figure 3 is a detached perspective view of the hook member and itsspider for connection to the shaft.

Figure 4 is a perspectivey view of the bobbin carrier; and j Figure 5 isa perspective view of vthe bobbin casing;

As shown in the drawings a spider 10 has a cylindrical central bushing11 for attachment to a rotary shaft below the bed plate of the machineas will be understood by those Skilled in the art, and has radiatingarms 12 with outer portions 13 projecting As is well forwardlyconcentric with the bushing and carrying at their endsan 'incomplete'ring Ysection 141 constituting part of the hook-ring,

the hook itself being at the point where. a part of the ring is missinga short .distance -behind the end 15. A groovel 16is formed on the innersurface of this ring at itsend to receive andv serveas a bearing for airim on the bobbin carrier. Theouteropenside of groove 16 is closed by asemicircular plate 17 fitting against and securedv to thefend of ring14; starting at'the. end 15v and eX-` tending around throughout``considerably more than khalf the Acircumference The semicircular plate17 has onvits outer-.facce projecting semicircularfiiange 18 rising Akona gradual incline from the surface at its `end` 19 to full height andextending aroundto 2O with its inner wall concentric with `the inneredge of plate 17 and its outer wall at the end 19 tapering inwardly tokguide vthe loop of thread. I1`he hook member 21ais`- shaped to form acontinuation of flange 18 but is curved slightly outward and carrieshook 22 at its end. The strip 23 spans the opening in the ring section14andlextends Vover the inner portion of the hook.

Thecarrier 24 shown in Figure 4has a urim 25 tting in the groove 16 Y.topermit turning of the'hook ring around it and is provided with asemicircularv projecting flange or portion 26, the ends of whichserve asstops as hereinafter explained, and which carries at its outer margin`in a ,plane at right angles to the axis a projecting plate likeextension 27 having on itspaced taperin ribs 28.

hat portion of the carrier 25 and flange extension 26 behind the centralportion of plate 27 are removed at 29 to permit the entrance of theneedle and thread loop. The ribs or stops 28 cooperate with means notshown 'for preventing the carrier from rotating with `the hook; rA postor pin 30is mounted on the end plate 31 ofthe carrier 24 to receive thecylindrical central portion of the bobbinV casingor holder. This post`is not however mounted at the, exact center of rim 25 but at a pointbelow and to the right at an angle of about forty-fivedegrecs as will beseen by reference to Figures 1 and 2, so that the center line. of post30 will be eccentric to the center line of the drive shaft and to thepath ofthe hook. The center point for the matching inner surface ofgroove 16 and outer surface of rim 25 is indQatBdfinEigure l at a,whereas the center of post 30 and of the outer wall of the bobbin casingwhich lits on it is indicated at b. Broadly considered, this offsettingor eccentric arrangement of the bobbin and its casing 'in referencetothe path of the hook is well known inthe-art and is forthe purpose ofallowing room or clearance for the needle at the -top and particularlyto `providefor the proper angle on the guide surface V-frfor'n `theperiphery to the end of t-therholden just beyond the needleY toproperly,-s`pr'ealdg the. loop and cause it to pass y'around ftheholder. The necessity `for this l5 loffset: andyclearanc'e has in` allforms in which, it yhas heretofore been used placed 'what was-consideredaliXed maximum limit #ongthesizeof bobbin which` could be successfullyusedwith a` carrier and hook ring -of ay 'particular diameter, andconversely liasyfprevented any reduction in the diameter of the hookring and its relative periphferal 'speed compared to the rate ofrevolution, when used with a bobbin of definite 255 size. -I-havehowever discovered meansrby "whichrthefd-iameter of thehook ring may be:reduced with a bobbin of fixed size or the '-'diameter of the. bobbinincreased with a .floekr-ing o fxdefinite size by van amount ofeq'ual tothe thickness of the bobbin casing whilerstillleavingthe necessaryoffset elearance', and in theform shown it resides in the; structuralVforni Aand i cooperative relation I offt'hecarrier and bobbin casingwhich fitsl in it. t-will'benoted'thatawhile the post 1 30 isieccentrically arranged in the` carrier7 the-,inneriwall of the carrieris transversely curved but'is,longitudinally parallel to post '30 'fr'omitsouter edge to its base plate 3l, and thus forms a substantiallycylindrical `clfamber for the ybobbin but of greater diameter-,and aswill be seen by reference to Fig- 'ure 2 vitsdepth throughout itscircumfer- 'lenoebetween theends of plate 26 is somewhat less than halfthe lengthof the cylin- "drieal-bobbin easingwhich -lits in it.

The bobbin casing shown in Figure 5 has an outer cylindrical portion orshell 32 and a'central sleeve 33 adapted to receive a bob- V bin-"andtofit on the post 30 ofthe carrier.

The material at the inner end of the cylindrical portion 32 is removedto a uniform distance from the end throughout about *half of thecircumference from the reinainingfendll to the end 35, leaving an end jmargin 36 oir that portion in a plane parallel'to thelplane'of theend'of the balance of the.: cylindrieal'portiom but removed therefrom adistance; substantially equal to the dis- 50 tance from the outer faceofthe rim 25 of the carrier-to the inner face of bottom plate 3l.

The'offset from center of post 30 and the di- `ameterofy cylindricalcasing 32 is such that :when the casing is 'insert-ed in the carrierover post 30 with the 'full length part at the upper portion with theends 34 and 35 on an angle of about forty live degrees upwardly from theleft in Figure l, the full length part will fit within the cylindricalopening in carrier 24 to its base plate, but the margin 36 will abut theouter end face of rim portion 25 and at its central portion its innersurface will be in line with the in ner surface of the rim member 25 asshown in Figure 2. It will be observed that this overlapping oralignment of a part of the ca-sing 32 with the rim member 25 instead offitting entirely within that rim as heretofore renders it possible touse a bobbin casing, and consequently a bobbin, in the particularcarrier shown having a diameter greater by an amount equal to thethickness of the casing than would otherwise be possible. rlhat wouldgive the bobbin greater capacity with no change in clearance or diameterof the hook ring or its peripheral speed. To vput it differently, thenovel construction permits of a greater eccentricity or lateraldisplacement of the bobbin axis relative to the hook axis than wasbefore possible with the same bobbin and bobbin carrier diameters, andpermits of the use ofa bobbin of given diameter in a hook ring ofsmaller diameter than before. lVhile the reduction in diameter by thethickness ol' the casing and the consequent reduction in Iperipheralspeed of the hook may seem a slight structural change, the increasedspeed and efliciency of operation resulting from it are in fact veryremarkable in practical operation.

The cylindrical,portion of the bobbin casing has across and secured toits outer end a member 3 7 which. carries at its middle portion sleeve33 and which extends heyond the margin of the cylindrical portion at theleft in Figure 'l and there assumes the form of a liange 38 curvedlaterally and circumferentially to serve as a thread defiector or guide7and terminating at its upper outer end in a tapered or pointedlingerv39. This linger 39 on its inner and under surfaces engages theend el() of the flange extension 2G to aid in preventing the casing fromrotating in the carrier. 'lhe member 37 also projects slightly beyondthe margin of the casing cylinder at its other end at Lll as shown atthe right in Figure l, and its projecting edge engages the end 42 of theplate extension 2G on the carrier to cooperate with linger 39 inpreventing the casing from rotating in the. carrier. In Figure 2 anempty bobbin -l3 is shown iu the casing to illustrate the relations ofthe parts9 and it will be seen that its lower portion extends outsubstantially to the inner surface of the carrier opening with nothinginterposed between, and thus makes contact with that surface. lt will beunderstood by those skilled in the art that in operation the lllinclinan needle descends between plate '27 and the face or plate 17 inFigure 2, and that the loop is there caught by the hook and is carriedforward by it, speeding over flange 38 and passing around thebobbinholder mechanism. lt operates in a manner well known, and furtherdescription is unnecessary.

Having thus described my invention, what is claimed as new and desiredto be secured by Letters Patent is: Y Y

l. In a rotary hook sewing machine comprising a non-rotatable carrieradapted to be mounted in a rotary hook and formed with a bobbinreceiving chamber, a bobbin casing having a bobbin encircling` portioncut away at one side and mounted in said carrier with said portionextending into said chamber except at the cutaway side thereof, and withthe bobbin axis laterally displaced from the hoolz:` aXis by a distancegreater than would be possible if said casing were not cut away.

2. In a rotary hook mechanism for sewing machines comprising anon-rotatable carrier having a bobbin receiving` chamber open at one endand of less depth than the length of the bobbin encircling part which iscut away at one side and is mounted in said carrier with the uncutawaypart of said portion extending into said lchamber and with the bobbinaXis closer to one side of the carrier than would be possible if thatside of the carrier were not adjacent the cutaway portion of the casing.

3.`Rotary hook mechanism for sewingv machines comprising a carrierhaving a tubular chamber therein open at one end, the wall of whichterminates throughout most of its cimcumference on a transverse plane atthe open end, a bobbin casing having a cylindrical shell of lessdiameter than said chamber, the material at the end of said shellthroughout a portion of the circumference extending beyond that of theother portion a distance approximately equal to that of the depth of thechamber from said plane, means for guiding said casing to position withthe end portion of greatest length within said chamber extendingsubstantially to the ybottom around the upper portion and with theshorter portion of the cylindrical shell abutting the end of the chamberwall at said plane and with its inner surface in line with the innersurface of said chamber on a line at the lower portion, and means forholding said casing in position in said carrier.

#l Rotary hooi; mechanism for sewing machines comprising a carrierhaving a tubular chamber therein open at lone end, a casing for a bobbinof materially greater length than the depth of said chamber havingv acylindrical portion ofless diameter than said chamber, means for holdingsaid casing in eccentric position on said carrier with a part of saidcylindrical portion abutting at its end an end portion of said chamberwall with the inner surfaces in line alongvthe lower portion and havingthe opposite side of said casing at and beyond the middle removedinwardly from the carriers margin a predetermined distance to permit theformation and spreading ofthe loopK i 5. Rotary loclr mechanism forsewing machines comprising a carrier having a rim and a bobbin casingextending within said carrier throughout part of its circum ference andeccentrically spaced from ythe rim within that part and abutting the endof the carrier in the opposite part with their inner surfaces in linewhereby the bobbin will be in Contact on that side throughout part ofits length with lthe casing and throughoutthe balance of its lengt-lrwith the carrier.

6. ln a. rotary hoolr mechanismfor sewling machines comprising' anon-rotatable carrier having a bobbin receiving chamber open at one end,a bobbin casing comprisinga bobbin encircling part which is cut away atone side, and means for holding the bobbin casing in place in thecarrier with the outer end portion of the casing at the cutaway side ofthe latter lying in front of' the adjacentportion of the carrier andwith the remainder of said encircling portion extending into thechamber.

7. Rotary hook mechanism for sewing machines comprising a carrierprovided with a peripheral bearing rim and a concentric chamber closedat its bottom and terminating at its open end throughout most of itscircumference at fthe outer margin of said rim with a depth materiallyless than vthe length of a bobbin and having a se mental plate extensionat the top, a gui e post carried by the bottom wall of said chamber in aposition offset downwardly and laterally from the center line of saidchamber a predetermined amount, a bobbin casing having a cylindricalshell fitting longitudinally and laterally a bobbin throughout half ofthe circumference but terminating sho-rt of the end throughout amaterial portion of the circumference by an amount equal to the depth ofsaid chamber, a. cross member at the base of said shell carrying acentral guide sleeve adapted to fit said guide post, the diameter ofsaid shell being such that when in position on the post the end of theshort portion of the shell will abut the outer margin of said rim withthe interior surfaces` of the shellY and chamber in line near thebolt-tom, a thread deflecting flange at one end of said cross memberprojecting beyond the margin of the cylindrical casing, properlytapered, and provided at its end near and facing the top with a pointedfinger adapted at its base to engage one end of said segmental platellt) Vextension on theY carrier ande `projecting portion atl theV otherend of said cross` member to engagevthe. other end of saidplateextension to hold the. easing and carrier in proper .position againstrelative rotation.

8. Rotary hook mechanism forV sewing machines comprising a carrierlia-ving*T a chamber' therein open at o-ne end with ay segmental plat-eexensionat, the central upper part over said open end and pro- 1ridedwith en upstanding flange and means adapted for engagement To preventrotatiom a oylindroalhobbin casing mounted eccentrically in said carrierawa-y from that portion over which the hook passes irs after enga-jingthe loopj a cross member on the end of Said bobbin casing' extendingbeyond its margin and beyond the margin of the Carrier in the form of a.tapering thread guide flange terminating' in a pointed finger nearthetop facing the top and adj aeent the end (if-said plate extension andabul'tziugy; Said end at its base to prevent roraiion` and Carryingmeans at its other end 'for euglaging the other :id of .Quid plateextension.-

9. bobbinoasingr adapled to be re1norably inserted in the non-rota'ablecarrier or' a rotary hooi sewing mechanism and comp-rising` a shell openat its inner end and a peetv attached to the other end or the Shell andadapted t0 nass axially through a bobbin inserted in the easing. ,QuidShell comprising a portion covering the peripher)Y of lthe inserl'edbobbin for Substantially the full axial depth of the lat/ter et onesnide of the post and at the opposite Side of fhe poet being` cui,avverto expose a eoneiderable portion or' he periphery of the bobhinforthe purpose specified.

ln testimony whereof l affix my Signature.

RICHARD K. HOHMXNN.

